WebiyoAnswer engine optimization (AEO) is the work of getting a business named inside AI answers. Every AI tool gets there in two steps: it retrieves sources, then it chooses which ones to use. Here is how ChatGPT, Perplexity, Google, Gemini and Claude each do that, taken from their own documentation.
Each company's own documentationOriginal research linkedUpdated October 2026
Google's Knowledge Graph starts answering questions directly.
The retrieval-augmented generation paper is published.
ChatGPT launches on November 30 and reaches 100 million users in two months.
The GEO paper shows visibility in AI answers can be raised by up to 40%.
ChatGPT is widely reported to pass 1 billion weekly users.
Search engines were answering questions directly a decade before the current AI wave.
Google's Knowledge Graph, launched in 2012, was the first big step away from a plain list of links. It let Google answer some questions with facts about a person, a place or a thing, instead of only pointing to pages about it.
Then it moved fast. ChatGPT launched on November 30, 2022 and reached 100 million users within two months, faster than any consumer app before it. Perplexity launched its answer engine, with sources shown inline, eight days later. Microsoft launched Bing Chat, powered by GPT-4, in February 2023. Google showed AI search summaries at its developer conference in May 2023 and rolled them out to everyone in the U.S. a year later as AI Overviews.
The terms "answer engine optimization" and "generative engine optimization" both came out of this stretch. Being the answer had become something a business could work toward or lose.
Neither is new. Everything sold under the name AEO applies two pieces of published research.
Retrieval-augmented generation comes from a 2020 paper by Lewis and colleagues at Facebook AI Research, University College London and NYU. They found that a model that looks something up before answering, instead of relying only on what it memorized in training, gives answers that are more accurate and easier to check, because it can point to where the information came from.
Lewis et al., arXiv 2005.11401Three years later, a separate paper tested whether publishers could change how often their material was used in generated answers. They could, by up to 40% in the paper's tests. That paper is where the term GEO comes from.
Aggarwal et al., arXiv 2311.09735AEO gets talked about as one thing. Each AI tool finds and ranks sources through its own system, and the differences decide what helps.
ChatGPTWhen a question needs current information, ChatGPT runs a web search and reads the results before it answers. OpenAI's documentation says those results come from Microsoft's Bing, so checking how a page does in Bing is often the fastest way to see what ChatGPT can see.
OpenAI, ChatGPT search
PerplexitySearch is the whole product. One question can pull in more than 60 candidate sources, which are filtered down in stages. Sections of a page are scored against the question separately, so one strong paragraph on a long page can be pulled forward and credited. Perplexity doesn't publish its ranking formula, and neither does Google.
Perplexity, search API architecture
Google AI Overviews and AI ModeGoogle runs several searches behind one question. It calls this query fan-out: the question is split into related searches, run in parallel, then combined into one answer with links. Google says a page needs nothing special to appear beyond being indexed and eligible for a normal search snippet.
Google Search Central, AI features
GeminiWhen grounding is turned on, Gemini decides for itself whether a question needs a live search. It writes the query, runs it, and answers from what it found, with its sources listed.
Google, grounding with Google Search
ClaudeClaude searches in rounds. It can run one search, read what came back, and decide it needs a narrower second search, repeating until it has enough to answer. Every answer drawn from the web links back to its source.
Anthropic, web search toolEvery one of these systems retrieves sources before it writes. It can only retrieve what is there to find: pages that are readable, current and worth quoting.
The headline prediction missed. What changed instead is how fast people took up AI tools, and how few small businesses have responded.
The drop in traditional search volume Gartner predicted by 2026. It hasn't happened. Google still handles the large majority of searches.
Gartner, February 2024Weekly ChatGPT users, as widely reported in August 2026. That is up from 900 million six months earlier and 400 million a year before that.
Widely reported. Not confirmed by a standalone OpenAI statement.Estimated share of Fortune 1000 companies doing AEO work. Among small and local businesses it is far lower, mostly because owners haven't heard the term.
AI Rank Lab, AEO Market Report 2026None of these is wrong. What matters is knowing which one describes you, and how fast that could change for your customers.
Mostly larger companies today, and a growing number of small businesses.
They know it's happening and haven't started. There may be time. It depends on how fast this moves in their city and trade, and that varies a lot.
The largest group among small businesses by far. Most owners haven't run into the term yet.
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41 AI search terms in everyday words, each tied to its source.
Open the glossary21 items sorted by evidence: what is proven, what is worth doing, and what to stop.
Open the checklistWhere the two overlap, where they split, and which one matters more for you.
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Answer engine optimization (AEO) is the work of getting a business named inside an AI-generated answer from tools like ChatGPT, Google AI Overviews, Perplexity or Gemini, instead of only ranked in a list of links.
In practice, yes. Generative engine optimization (GEO) is the academic term, from a 2023 research paper. AEO is the term agencies and business owners use more often. Both describe the same goal.
OpenAI's documentation says ChatGPT search results come from Microsoft's Bing. That makes Bing worth checking alongside Google.
No. Google says a page needs to be indexed and eligible to show a normal search snippet. There are no extra requirements.
Ask the AI tools the questions your customers would ask, with your town named, and note who gets named. Or send your website through the free audit and we will do it for you within 24 hours.
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